ZPortal

ZPortal is a PK3 created by Mike Hill (Cutmanmike) for Doom II and the GZDoom source port. It is directly inspired by the produced by, and attempts to replicate the kind of puzzle gameplay featured in that game into Doom. Originally released as a single-level tech demo called ZDoom Portal Gun, it was expanded into a full-fledged puzzle mod and released on May 29, 2008.

ZPortal is set in a hub composed of six levels (plus a bonus time attack map), and features gameplay very similar to the Portal demo. There is no combat and no conventional enemies: instead, gameplay is entirely focused around puzzle solving through the usage of portal guns: these are capable of creating two portals at any point they are fired at, which the player is then able to travel through at will. Correct placement and timing of the portals is key to solve the numerous puzzle challenges presented in the levels, and the mod also includes multiple types of portal guns which feature slightly different behavior in order to tackle some of the more complex puzzles.

Soundtrack
All music tracks inside the PK3 are s rather than MIDIs.
 * MAP01: "Compression of Time" by (from )
 * MAP02: "Forested Temple" by Nobuo Uematsu (from )
 * MAP03: "The Salt Flat" by Nobuo Uematsu (from Final Fantasy VIII)
 * MAP04: by Andres Koropecki (koro)
 * MAP05: "Doom Castle" by (from ) and  by David Newton (DavidN)
 * MAP06: "Succession of Witches" by Nobuo Uematsu (from Final Fantasy VIII)
 * MAP07: "Cutman Stage" by (from )